In a communication system, a transmitter modulates a signal onto a radio frequency (RF) carrier, and transmits the signal to a receiver over a communication channel. At the receiver, a low-noise amplifier (LNA) typically amplifies the received signal (which may include the desired signal, noise, and undesired jammers) and provides the amplified signal to later receiver stages for processing. LNAs are usually designed to have a low noise figure to amplify low level desired signals without introducing excessive noise. On the other hand, when the strength of the desired signal and/or the jammer is high, it is desirable for the LNA to have good linearity, or low distortion, so that the jammers do not corrupt the desired signal. The design goals of low noise figure and good linearity are often conflicting, and a single LNA design must often trade off one for the other.
It would be desirable to automatically determine preferred operating characteristics for an amplifier such as an LNA, and dynamically adjust the amplifier's parameters during operation to optimally trade off noise figure for linearity.